28 ROYAL SOCIETY OF CANADA 



and grey slates, which have, along the contacts, been changed to staiiro- 

 lite and mica slates and schists, the alteration being in this case due to 

 local causes. Further from the contact, the slates, while tilted at high 

 angles, present the aspect of dark-grey, sandy and argillaceous sediments. 



These gabbro rocks outcrop at a number of points through the slate 

 belt, and in every observed case the same phase of alteration is visible. 

 Instead of these rocks being Laurentian, they are therefore clearly of 

 later date than the slates which they penetrate, and as these are of Silurian 

 age, the intrusives must be in part at least post-Silurian. Along the 

 outer zone of these gabbros there are occasional pockety masses of 

 nickeliferous pyrrhotite, which have been sometimes compared with the 

 nickel deposits of Sudbury, Ont. In point of time they are, however, 

 widely different, since no Huronian rocks are visible in this part of the 

 province. " 



Closely related to the Silurian rocks, although much doubt existed 

 for many years as to their true horizon, is the group found on the east 

 side of Passamaquoddy bay, near the outlet of the Magaguadavic estuary, 

 and known as the " Mascarene series." The rocks are shales and slates 

 of various colours, often reddish or purple tinted, which are cut by 

 masses of green diabase and felsite, which have altered the strata along 

 the contact. In the lower part there are other masses of felsite, which 

 on lithological grounds were at one time regarded as possibly Huronian. 



The examination of these felsites show them, as elsewhere, to be 

 intrusive in the shales of this series, and therefore newer. In the 

 shales themselves fossils are found at a number of places. They are 

 mostly shells, but certain of the shell-bearing bands also hold well defined 

 .plant stems, so that as a whole the rocks have the aspect of lower 

 Devonian rather than of Upper Silurian sediments. As a series, they 

 rest upon the Upper Silurian fossil-bearing slates of Letite. They 

 are overlaid unconformably at several points by the red upper Devonian 

 beds of the Perry group, and between tliese two divisions there are in 

 places heavy flows of red felsite, which on first sight resemble inter- 

 stratified beds. The felsite outflow was, however, older than the Perry, 

 since large pebbles from it are found in the basal conglomerates of 

 the latter. Stratigraphically the Mascarene series may be placed be- 

 tween the Letite Silurian and the Perry sandstone, and may be regarded 

 as lower and middle Devonian, or not far from the characteristic 

 Devonian of St. John and vicinity. 



The rocks of the Perry group have furnished much material for 

 discussion. As first examined in Maine by Dr. Jackson, and subse- 

 ouently by Sir William Dawson and Professor Hitchcock, they were pro- 

 nounced to be a part of the Devonian system, this claim being well estab- 



